In general, the double-coated adhesive tape is prepared by forming a pressure-sensitive adhesive layer on both sides of a tape support such as a paper, a non-woven fabric, a film or sheet of a foamed product, a plastic film, etc. Those tape supports have fine pores or do not entirely have pores. Therefore, in order to form a pressure-sensitive layer on both sides of the support, a pressure-sensitive adhesive solution or aqueous dispersion must be coated on both sides of the tape support respectively.
The double-coated adhesive tape using a tape support having cushioning properties such as a paper, a non-woven fabric, a film or sheet of a foamed product, etc., which are conventionally used, exhibits good adhesive properties to an object to be adhered even if the surface thereof is a rough surface, due to the cushioning properties of the tape support. On the other hand, such double-coated adhesive layers provided on both sides of the tape support are separated by the tape support, in the event that the adhesive tape is rapidly unwound from a tape rolled state or an external force is applied to an object adhered with the adhesive tape, delamination tends to occur in the tape support, and also where the adhesive tape is wound into a rolled state by interposing a release paper or release film therebetween and stored, the pressure-sensitive adhesive layer partially impregnates into the tape support, and as a result, the thickness of the adhesive tape becomes ununiform or a so-called gapping occurs, thereby markedly lowering the commercial value.
On the other hand, use of a porous tape which has been subjected to a physical perforation treatment is proposed to prevent the delamination. However, since the tape support is thick and the pore intervals are long, the delamination is not effectively prevented. Further, since it is difficult for the pressure-sensitive adhesive layer to be sufficiently charged within the pores at the preparation, the pressure-sensitive adhesive layer is pressed into the pores with the passage of time and such portions become the sinked shape, markely deteriorating the commercial value.
Further, in order to prevent an ununiformity of the tape thickness due to impregnation or gapping, an attempt has been made that the tape support is not used and the adhesive function is given with only the pressure-sensitive adhesive layer. However, only the pressure-sensitive adhesive layer lacks self-supporting properties, the handling is difficult and deformation easily occurs during handling and operation.